Novel substituted silver halide developing agents



United States Patent Office 3,061,434 Patented Oct. 30, 1962 3,061,434 NOVEL SUBSTITUTED SILVER HALlDE DEVELOPING AGENTS Milton Green, Newton Highlands, and Warren E. Solodar, Watertown, Mass., assignors to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware No Drawing. Filed Aug. 26, 1957, Ser. No. 680,406 12 Claims. (CI. 96-66) This invention relates to novel chemical compounds and more particularly to certain novel chemical compounds useful in the development of photosensitive silver halide elements.

One object of this invention is to provide novel chemical compounds and the syntheses for their preparation.

Another object of this invention is to provide novel photographic developing agents, products, compositions, and processes for the development of silver halide emulsrons.

Other objects of this invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the products and compositions possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description.

The novel compoundsof this invention may be represented by the formula:

Mull-X wherein Ar is an aryl nucleus, such as a benzene or naphthalene nucleus; each Z is an alkyl group, preferably a lower alkyl such as methyl or ethyl, or a halogen such as chlorine; in is O, 1, 2 or 3; n is 0, 1 or 2; X is a primary, secondary or tertiary amino, or a nitro group; and Y is a p-dihydroxyphenyl, a p-bis-acyloxyphenyl, an o-dihydroxyphenyl, an o-bis-acyloxyphenyl, a p-bis-alkoxyphenyl or an o-bis-alkoxyphenyl group.

In a preferred embodiment, AI is a benzene nucleus, X is a primary amino group and such compounds may be represented by the formula:

(B) Zm ir-o-Qnm Zn wherein Y, m, n, and Z have the same meaning as above. The preferred compound within the group represented by Formula B is:

I OH

p-Aminophenoxyhydroquinone of ortho or para dialkoxyphenolate with a nitro aryl halide compound at an elevated temperature, dealkylating the respective alkoxy groups and reducing the nitro group.

Alternatively, the hydroxyl groups formed by the dealkylatlon reaction may be protected during subsequent reactions, e.g., diazotization, by acylation, for example by carbethoxylation, acetylation, etc. which can be effected most conveniently before reduction of the nitro group.

Where the secondary or tertiary amine derivatives are desired, the amino group may be suitably alkylated, preferably before removing the hydroxy protective groups.

The following example illustrates the preparation of compounds within the scope of this invention and is given for purposes of illustration only.

Example I 2,5-dimethoxyphenol was prepared according to the procedure of Burger in the 'JACS 75, page 1359 (1953). The potassium salt of 2,5-dimethoxyphenol was prepared according to the procedure of Gilman in the JACS 61,'

page 1370 (1939). An intimate mixture of 25 g. of 2,5- dimethoxy-potassium-phenolate (0.12 mol), 25 g. of p fiuoronitrobenzene (0.175 mol), 0.5 g. of 2,5-dimethoxyphenol, and 0.2 g. of copper powder (prepared as per Organic Syntheses, Collective Volume II, page 446), is maintained at 155 to 160 C. for one hour. The mixture darkens initially, melts completely in about 3 minutes and ebullates for approximately the hour, gradually becoming light amber in color. The melt is poured into a mixture of 200 cc. of ice water and 15 cc. of 3 N sodium hydroxide. An amber oil separates which soon solidifies. The solid is filtered oif and crystallized from 'cc. of ethanol. The resultant product, 25 g. of light yellow crystals, is vacuum dried over phosphorus pentoxide, and melts at 76 to 76.5 C.

Analysis of this product, calculated as p-nitrophenoxyhydroquinone dimethyl ether, C H NO gives:

Calculated (percent) 61. 1 4. 8 5. 1 Found (percent) 61. 0 4. 9 6.2

0,0'-diacetate are obtained as white needles, melting at 111 to 113 C. A solution of 3 g. of the above product in cc. of warm ethanol is hydrogenated with 2 atmospheres of hydrogen in the presence of 5 g. of a palladium-barium sulfate catalyst. The catalyst is removed by filtration and the solution concentrated to approximately 20 cc. Crystallization is induced by scratching the Wall of the container, yielding 2 g. of p-aminophenoxyhydroquinone- 0,0'-diacetate, a white, crystalline material melting at 112 to 113 C.

Analysis of this product gives:

0 I H N Calculated as O l-1 5N0 (percent) 63. 9 5.0 4. 7 Found-(perceut). 63.8 5. 3 4. 7

The product of Example 1 can be used directly in subsequent diazotization and coupling reactions.

p-Aminophenoxyhydroquinone may be prepared by the hydrogenation, in the presence of a palladium-barium sulfate catalyst, of p-nitrophenoxyhydroquinone which has Example 2 An aqueous solution of approximately:

Percent p-Aminophenoxyhydroquinone 2 Sodium sulfite 2 Potassium bromide 0.5 Sodium hydroxide 2 The novel developing agents of this invention may also be used in diffusion transfer reversal processes such as disclosed in US. Patent No. 2,543,181, issued February 27, 1951, to Edwin H. Land. Suitable silver halide solvents such as sodium thiosulfate and a viscous reagent, e.g., sodium carboxymethyl cellulose, may be added to the composition of Example 2 to render it suitable for use in such processes.

It will be apparent that the relative proportions of the components of the developer compositions set forth above may be varied to suit the requirements of the operator. Thus it is within the scope of this invention to modify said developing compositions by the substitution of preservatives, additional developing agents, alkalies, silver halide solvents, etc., other than those specifically mentioned. It is also contemplated that where desirable the said developer compositions may be modified by the inclusion of other common components of developer compositions such as restrainers, accelerators, etc. Similarly, the concentration of the developing agent may be varied over a wide range and where desirable said agent may be disposed in the photosensitive emulsion prior to the exposure of said emulsion.

Particularly useful developing compositions also contain a small amount of an auxiliary or accelerating developer such as Metol (p-methylaminophenol), benzylaminophenol or a 3-pyrazolidone, such as l-phenyl-3-pyrazolidone, etc. The preferred accelerating developer is 1- phenyl-3-pyr-azolidone.

The novel acyl compounds of this invention are useful chemical intermediates. They are especially useful in reactions wherein it is desired that the reaction be restricted to the amino group and where it is desired that the hydroxyl groups be protected during reaction and yet readily regenerated after the reaction is completed. In particular, the novel acyl compounds of this invention are useful as intermediates in the preparation of azo compounds, in accordance with the procedures disclosed in the copending application of Milton Green, Serial No. 680,403, filed August 26, 1957.

When employed as photographic developing agents the novel amino compounds of this invention may he introduced in the form of the free base or as salts thereof, such as the hydrochloride. Thus the salt may be employed where the developing agent is to be incorporated in, on or behind the silver halide emulsion or where one desires to prepare a dry developer composition, the solvent being added to the dry composition prior to use.

Since certain changes may be made in the above processes, products and compositions without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A photographic developer composition comprising an aqueous alkaline solution of a first and a second silver halide developing agent, said first silver halide developing agent being a compound of the formula:

wherein Ar is a phenylene nucleus, X is an amino group, and Y is a dihydroxyphenyl silver halide developing radical, said second silver halide developing agent being capable of accelerating said first silver halide developing agent.

2. A photographic developer composition as defined in claim 1 wherein said second silver halide developing agent is a 3-pyrazolidone.

3. A novel photographic developer composition as defined in claim 1 wherein said second silver halide developing agent is l-phenyl-3-pyrazolidone.

4. A novel photographic developer composition as defined in claim 1 wherein said first silver halide developing agent is p-aminophenoxyhydroquinone.

5. A method of developing a silver halide emulsion which comprises treating an exposed silver halide emulsion with an aqueous alkaline solution of a silver halide developing agent of the formula:

wherein Ar is a phenylene nucleus, X is an amino group, and Y is a dihydroxyphenyl silver halide developing radical.

6. A method as defined in claim 5 wherein said silver halide developing agent is p-aminophenoxyhydroquinone.

7. A method as defined in claim 5 wherein said silver halide developing agent is disposed prior to exposure in a photosensitive element containing said emulsion and the solution containing said silver halide developing agent is formed by permeating said photosensitive element with an aqueous alkaline solution capable of solubilizing said silver halide developing agent.

8. A photographic product comprising a support, a layer containing a silver halide emulsion on said support, and a silver halide developing agent in a layer on the same side of said support as said silver halide emulsion, said silver halide developing agent being a compound of the formula:

wherein Ar is a phenylene nucleus, X is an amino group, and Y is a dihydroxyphenyl silver halide developing radical.

9. A product as defined in claim 8 wherein said product contains a second silver halide developing agent which is capable of accelerating the first-mentioned silver halide developing agent.

10. A product as defined in claim 9 wherein said second silver halide developing agent is a 3-pyrazolidone.

11. A product as defined in claim 9 wherein said second silver halide developing agent is l-phenyl-3-pyrazolidone.

12. A product as defined in claim 8 wherein said silver halide developing agent is p-aminophenoxyhydroqninone.

References Cited in the file of this patent UNITED STATES PATENTS 2,604,399 Donovan et al July 22, 1952 2,698,244 Land Dec. 28, 1954 2,751,295 Salminen et a1 June 19, 1956 2,777,879 Spiegler Jan. 15, 1957 2,780,647 Spiegler Feb. 5, 1957 2,835,575 Cowden et al May 20, 1958 OTHER REFERENCES Mees: The Theory of the Photographic Process, Macmillan (pages 552, 553, 558-560). 

1. A PHOTOGRAPHIC DEVELOPER COMPOSITION COMPRISING AN AQUEOUS ALKALINE SOLUTION OF A FIRST AND A SECOND SILVER AGENT BEING A COMPOUND OF THE FORMULA: 